1. Field of Invention
This invention relates to magnifying devices, specifically to magnifying devices used with video display screens such as those found in computer monitors and television sets.
2. Description of Prior Art
Much of the modem practice of creating and using interactive computer simulations, known as "virtual reality", relies on the users of such systems having a feeling of immersion within the computer generated worlds depicted on their display screens. This illusion is typically achieved by using devices that create a wide angle, or panoramic, view of the display screen. The present invention is one such device.
The most commonly used apparatus to achieve the illusion of visual immersion is the head-mounted display. These displays consist of one or two very small display screens mounted directly in front of the user's eyes. Special optics allow the user to focus on the screens positioned only inches from the eyes. These small displays are attached to a helmet or similar head gear that must be worn by the user. There are many disadvantages to such an apparatus. Among them are:
(a) Price--Two display screens with all of their supporting circuitry are very expensive. Prices for professional models can range from six or seven thousand to over one million dollars. Average consumer models typically cost about one thousand dollars, and new low-quality versions for use with electronic games still average approximately 300 dollars.
(b) Resolution--The small display screens used in head-mounted displays typically have a resolution less than one-third that of the typical television. This makes for an unacceptably grainy picture. One investigator noted that if one's eyesight had the same resolution as is found in a head-mounted display, that person would be classified as officially blind.
(c) Field of view--In order to keep the poor screen resolution of small displays from becoming totally unusable, most manufacturers of head-mounted displays compromise by not greatly magnifying the image. Most settle for an image with a 60 degree-70 degree horizontal field of view. Researchers generally agree that a field of view greater than 100 degrees is necessary to achieve an illusion of immersion.
(d) Weight--Two display screens with all of their supporting circuitry, helmet and mounting hardware are very heavy. Also, many models use added weights on the back of the helmet to counterbalance the weight of the displays. The result is a apparatus that tires the user, particularly in the muscles of the neck and shoulder. Also, the inertia that is built up in moving the head with a head mounted display from side to side can painfully wrench a user's neck.
(e) Ease of Use--Typical head-mounted displays systems pre-suppose an advanced level of expertise on the part of the user. Systems are difficult to set-up and maintain. Many are not readily compatible with common existing computers or television systems and require the purchase of additional intermediate hardware and software.
The use of magnifying devices with video display screens is shown in a number of patents. U.S. Pat. No. 5,119,239, U.S. Pat. No. 5,061,052, U.S. Pat. No. 5,048,928, U.S. Pat. No. 4,802,756 and U.S. Pat. No. 4,712,870 depict magnifying apparatuses to be used with video displays. However, all are designed and intended simply to make the video picture somewhat easier to see, and do not in any way posses the capability to create an illusion of immersion for the user.